When the British and Irish Lions rugby team toured South Africa in 1974, they knew they would be in for some rough treatment. Willie John McBride, the captain of the touring side, came up with a plan. The Lions would retaliate early: when any player shouted “99” the whole team would hit the nearest opponent.

Sure enough, during an extremely violent match at Boet Erasmus Stadium, the call went up. JPR Williams, the Welsh full back, ran half the length of the pitch to join in the melee. It was violence but with a purpose. The referee was left with the choice of sending off either all or none of the team. Sure enough, not one player (not even JPR) was shown a red card.

Last week, the US authorities faced a somewhat similar dilemma when dealing with the HSBC money laundering case. The UK bank, which sponsors the Lions, has agreed to pay a $1.92bn settlement following accusations it enabled Mexican drug cartels to move money illegally through its US subsidiaries. However, the authorities decided against a criminal indictment, figuring it could jeopardise the bank and potentially destabilise the financial system.

A settlement was considered a healthy compromise. That may well be true in practical terms. Nevertheless, it raises the suspicion that some banks are not only too big to fail, they are also too big to indict. If that is true, it effectively means they are above the law. It is that kind of thinking that could really destabilise the financial system – it definitely deserves a red card.